Laws Of Motion Question 104
Question: A 60 kg body is pushed with just enough force to start it moving across a floor and the same force continues to act afterwards. The coefficient of static friction and sliding friction are 0.5 and 0.4 respectively. The acceleration of the body is
Options:
A) $ 6m/s^{2} $
B) $ 4.9m/s^{2} $
C) $ 3.92m/s^{2} $
D) $ 1m/s^{2} $
Show Answer
Answer:
Correct Answer: D
Solution:
Limiting friction $ ={{\mu } _{s}}R={{\mu } _{s}}mg=0.5\times 60\times 10=300\ N $ Kinetic friction $ ={{\mu } _{k}}R={{\mu } _{k}}mg=0.4\times 60\times 10=240\ N $ Force applied on the body = 300 N and if the body is moving then, Net accelerating force=Applied force ? Kinetic frictiontherefore $ ma=300-240=60 $
$ \therefore $ $ a=\frac{60}{60}=1\ m/s^{2} $
